Homemade sourdough is notoriously laborious to make, as you need to feed your sourdough starter every day to keep it alive and bubbly. Failure to feed your starter regularly can cause it to die, meaning you'll have to keep a backup starter you can break out if something goes awry.

A sourdough starter is a miniature ecosystem inhabited by various microorganisms that feed on the natural sugars in flour. If you neglect to feed your starter for multiple days in a row, the good bacteria that protect it can die, allowing mold to grow.

Thankfully, keeping a backup sourdough starter can be done without making a new one from scratch. As Cook's Illustrated points out, every time you feed your starter, you're left with an excess amount of starter that you'll usually discard; instead, save the excess in a separate jar to provide a backup to your primary starter.

To preserve it properly, cover the starter with a tight lid and store it in the refrigerator; this way, you'll only have to refresh it once a week. For long-term storage, thinly spread the starter on a piece of parchment paper, and let it dry at room temperature. Then, peel it off, break it into pieces, and store it in an airtight container for months.